The four companies that have settled in the past four weeks all refused to sign on to an earlier class-action lawsuit that would have paid them back with interest any money owed to them by Pilot, which had $31.4 billion in revenues last year. The holdout trucking companies were seeking triple damages and punitive damages in their lawsuits.

Jeffrey C. Kirby represents National Retail Transportation Inc. and Keystone Freight Corp. Both companies settled on March 4. Kirby said he could not disclose any details of the settlements because they were confidential. He would only say, "We've resolved our issues with Pilot."

Shoreline Transportation of Alabama Inc. settled on March 10 and Osborn Transportation Inc. settled on March 11, according to court records.

Three other companies have not settled and are continuing to pursue claims against Pilot in federal court.

Pilot attorney Aubrey Harwell said the company has made offers to those companies as well.

"Hopefully all will be resolved, but it's too early to know," he said.

Since an April 2013 FBI raid on Pilot headquarters, the nation's largest diesel retailer has conceded that employees cheated customers but has said that CEO Jimmy Haslam was unaware of the scheme. Gov. Bill Haslam has said he is not involved in Pilot's day-to-day operations.

Ten former Pilot employees have pleaded guilty to the fraud, which was known by a variety of euphemisms including "manual rebates." Last July, Pilot agreed to pay a $92 million penalty, and federal attorneys agreed not prosecute the company. Pilot agreed to pay another $85 million in Nov. 2013 when a federal judge approved a class-action settlement with 5,500 customers.